Apparatus for treating rubber



May 22, 1923. 1,456,211

W. H. BINES APPARATUS FOR TREATING RUBBER Originai Filed Dec. 29, 1920INVENTOR.

WiHiam H. Bihes GE. I ATTORNEY.

WILLIAM H. BIKES, OF AKRON, OHIO, IGNOB TO THE FIONE 'I'IBE AND RUBBERCOMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO.

Original application filed December 39, 1930, Serial Ho. 438,840,.Divided and this application flied July a of Ohio, have invented certainnew and useful Improvements in Apparatus for Tre'at ing Rubber, of whichthe following is a specification.

This invention relates particularly to an apparatus for treating rubberand is intends ed to improve some of the conditions present inmanufacturing said articles from this material, this application bein adivision of my prior application, Serial l 0. 433,840,

in filed December 29, 1920, which application was directed to the methodof treating the rubber and has eventuated into Patent No. 1,400,137,dated December 13, 1921.

In the manufacture of rubber stock by the ac extrusion method,particularly the extrusion of tread gums for the manufacture of treadsof pneumatic tires, the stock is placed in the cylinder or barrel of adie extruding machine in which it is acted upon by a hich forces therubber outwardly to the die opening. The opening is usually in the formof a long narrow slot, tapering toward its ends, the shape of thefinished tread strip. As the strip issues from the die opening, it ismore or less wavy orundulatory in the center due to the stresses put.into the gum as it is forced outward through the die.

In the general practice the tread strip, as

it issues from the machine, is received on a traveling belt, the speedof which is adjusted to the speed of the issuing strip of material sothat a determined stretch is given and the strip reduced to the widthdesired.

The strip is then cut into predetermined lengths, in some instancesbeing cooled by immersion in a trough of water.

The shrinkage which takes place in the tread strip in attaining itsfinal set is due either tocooling or to the relieving of the stresseswhich are placed in the tread upon being forced'out of the die, or' toboth causes, or for some other cause which has not yet been determined."In the ordinary 0 shop practice the inability to gauge or allow forshrinkage has caused much loss owing to the impossibility of cutting thestrip to the exact length required for subsequent speedofthebetSmaybereSerial E0. 483,156.

It has been found that the tendency for shrinkage may be overcome byplacing the tread strip under a certain degree of compression while itis still warm and as it issues from the tube machine, variable accordingto the characteristics of the stock, so that the tread may be accuratelycut as it issues from the extruding machine, a result which has not beenaccom lished heretofore. The explanation of t is fact may reside in thefact that enoughcompression is placed in the rubber strip so that, asthe subsequent shrinkage takes place in the rubber, a re serve isprovided which compensates for the shrinkage.

The present invention is directed to the apparatus for handling theextruded rubber strip by placing a certain and predetermined amount ofcompression in the rubber stock as it issues from the machine and beforeit is cut to length, so that accurate cutting may be obtained withoutthe loss incident. to the overlength cutting which has been prevalentheretofore and without recutting to size after the stock has taken itsset.

In the drawings:

Fig. 1 is a side elevation of an apparatus which forms one embodiment ofmy invention.

Fig. 2 is an enlarged view of the gearing between the two conveyorbelts.

In the drawings, 1 represents the extruding machine known in the art asa tubing machine provided with the large gear 2 to drive the screw forforcing the rubber outwardly through the die opening, the gear beingdriven by pinion 3 on the shaft ofthe motor 4.

Thetread strip 5, as it issues from the head 6 of the tubing machine, isreceived on an endless belt 7. This belt is driven b chain 18 or othersuitable means, a litt e faster but in timed relation to the speed ofthe oncoming strip so that the tread is drawn down to the proper width.

Arranged at the end of the belt 7 is a sec .ond conveyor belt 8 mountedon along table 9. Between the belts 7 and 8 is located any suitabledrivi mechanism so that the lated in re.- spect to the speed ofthe beltThis may 10 is carried on the shaft 11 of the belt 7 and a gear 12 onthe shaft 13 of the'belt 8. The said gears are connected by an idlepinion 14 adjustably mounted in a bracket 15. If it is desired to varythe speed of the belt 8 with respect to the speed of the belt 7, ap-

ropriate changes may be made in the gearing. The differential speedbetween the two conveyor and supporting belts is determined by thedifferent character of the rubber stocks used, -it having been foundthat some stocks r 're a greater degree of compression to o s theshrinking which occurs upon cooling and setting of the stock, due to thedifferent coeflicients of shrinkage.

The result of the slower movement of the belt 8 to the belt 7 is tointroduce into the tread strip, as itpasses over the gap between thebelts, a fixed and definite degree of compression. Upon the cooling orsetting of the stock, whatever shrinkage occurs will be drawn from thecompression within the stock itself. As a result it is possible to' cutthe stock immediately to the len he desired.

o perform this operation, I mount over the tread a knife, wire 'or othercuttinginstrumentality, illustrated at 16, which is so timed in itsoperation that it Wlll cut the desired lengths of material. The belt isdipped out of the path of the hife as shown at 17. Due to theimprovement which has been described in the foregoing specification, thecutting of the stock may be accurately done so there is no need for anyrehandlmg in preparation of the tread for the tire.

The particular form of hife is non-essential and workmen provided withshears are often employed for this work.

Changes in the apparatus may be made,

and it is understood that other means than the one shown herein me bedevised for placing compression within the hot tread strip issui fromthe die, so as to compem sate for en uent shrinkage uivalent means areintended to be covers by the appended claims and I do not intend to becompressing the rubber prior to the final setting thereof.

2. n apparatus for the preparation of raw rubber, comprising a devicefor forming the rubber in desired cross section, said device placing therubber under internal tension and heating the rubber and placing therubber under compression and before it has assumed its final set.

3. An apparatus for the preparation of row rubber, comprisin anextruding machine, a belt for receiving the rubber from the saidmachine, a second belt from which the first named belt delivers andmeans for operating said second named belt at a slower speed than thefirst named belt whereby the rubber in passin from the first to thesecond belt is place under compression.

4. An apparatus for the manufacture of rubber strips comprising aforming device for the strips, and means adjacent the form.- ing devicefor receiving the'stri s therefrom, the said receiving device ing soconstructed and operated as to place the strip under longitudinalcompression.

5. An apparatus for the manufacture of rubber strips comprising aforming. device for shapingthe strips in the desired crossection, saiddevice operating to place the rubber under internal tension, and meansfor receiving the strip from the formin device, said means being soconstructed an operated as to pression in the rection of its length.

6. An apparatus for the manufacture of rubber strips comprising an aparatus for shaping ru ber strips in the esired crosssection, a movingsurface adapted to receive the strip from the said shaping apparatus andmeans for re ating the movement of the receivi sur ace so that therubber is compremed ongitudinally.

7. An apparatus for manufacturing lengths of uncured rubber comprising ashaping mechanism, a belt for receiving the lengths from said shapingmechanism, and means for causing the belt to move at a slower s than theat, which the lengths issue from the s aping mechanism whereby therubber is placed under compression in the direction of its length.

8. An ap aratus for the preparation of uncured rub r comprisin a shapingmechplace the strip under comanisin, and means to receive and retard therubber as it issues from the shaping mecha- 9. An apparatus for thepreparing of un-- cured rub comprising a shap' mechanism for formingrubber in s i r ip's, and

means-to retard the forward end of the strips so that com ression is set11 therein.

IAM H. INES.

